Sainsbury's, Asda and Tesco have announced they are banning shoppers without face masks from entering their stores.

It comes as Britain's biggest supermarkets have recently added a number of new strict rules to their store policies to ensure both staff and shoppers stay as safe as possible as the coronavirus pandemic rages on.

The supermarkets' new guidelines follow the news on Monday that Morrisons will now refuse entry to anyone who isn't wearing a face covering and will ask those without one to leave if they aren't medically exempt.

Morrisons' chief executive David Potts said of the move: "Those who are offered a face covering and decline to wear one won't be allowed to shop at Morrisons unless they are medically exempt.

"Our store colleagues are working hard to feed you and your family, please be kind."

The supermarket has introduced new rules

So what new rules are Tesco, Asda and Sainsbury's introducing? Here's all you need to know...

What new guidelines will people have to follow in Sainsbury's?

Sainsbury's customers must now wear a mask or a visor, unless they are medically exempt. Security guards will be stationed at store entrances, and anybody not following the rules will not be allowed to enter.

Sainsbury's has also significantly reduced the number of people allowed in store at any one time, and will be enforcing the one-adult per household rule. As before, children are welcome.

The chain has stated that keeping people safe is its "highest priority", and that customers were given regular reminders to follow the rules amid the lockdown.

A spokeswoman for Sainsbury's said: "We continue to have a range of measures in place to keep customers and colleagues safe in our stores.

"We have greeters outside our supermarkets and busy convenience stores to limit the number of customers coming into stores and continue to remind customers to wear face coverings and shop alone if they are able to.

"We also have posters and regular Tannoy announcements."

Those who don't follow rules will be asked to leave stores

What are Tesco's new rules?

Tesco said it was still enforcing social distancing practices in store but was not looking yet at reintroducing measures such as one-way aisles.

"The safety of our customers and colleagues is our top priority and we already have extensive social distancing measures in our stores to ensure everyone can shop safely with us," the store said on Twitter.

"We are asking all our customers to wear a face covering when visiting our stores and have prominent signs in place to inform customers of the rules.

"However, there may be some customers who are unable to wear a face covering for medical or safety reasons and we have asked our colleagues to respect that and to not challenge them directly."

Those without masks won't be allowed in

Asda's new rules

Asda has announced those who refuse to wear a face covering without a valid medical reason will be refused entry.

In a statement, a spokesperson said: "If a customer has forgotten their face covering, we will continue to offer them one free of charge - but should a customer refuse to wear a covering without a valid medical reason and be in any way challenging to our colleagues about doing so - our security colleagues will refuse their entry."

What have local authorities said?

Local authorities have also promised to work with the Government to enforce rules in supermarkets.

A spokesperson at the Local Government Association (LGA) said: "We are aware that an ongoing concern among councils and enforcement officers relates to levels of social distancing, the use of face masks and infection control compliance at supermarkets and are pleased that the Government is currently looking into this.

"We will continue to work with councils and Government to ensure that any changes brought in to increase safety in our communities are done so effectively."